Question regarding dual voltage motors

[Surefire01]

I have a question regarding dual voltage motors. Commonly 3 phase low voltage motors sold today (in Europe) are specified as 230/400v delta/star. According to my understanding if this motor was installed in the UK it would have to be configured to run in star. If it were configured to run in delta it would mean that 400v would be impressed upon each winding which could reduce the life of said windings as each individual winding’s insulation is rated to withstand only 230v.
If this is the case and my application required that this motor should to be run in star/delta, am I going to stress the motor winding insulation unacceptably and shorten its life whilst its running in delta. Or will I have to find and purchase a motor who’s windings are happy to have 400v impressed upon them?

This didn’t seem to be a problem years ago when it seemed like any motor could be run in star or delta.

Thanks for your thoughts.

 

[LionelHutz]

There is no "could" about reducing the life. The motor would die a quick death if you attempted to run it in delta on a 400V system. If you want to use a star/delta starter on the motor, then you need a 400V/690V rated motor or a 6-lead motor rated for 400V when connected in delta.

There have never been motors that could be run in both star and delta on the same line voltage and still produce rated output for each connection.

 

[waross]

I agree with Lionel.
Quick death;- Probably less than one minute.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[Surefire01]

Thanks for that chaps, I kinda suspected what you said, just wanted to be sure.

 

[jraef]

Use a solid state soft starter instead of a star delta starter. Better in all aspects. Star delta starting is an anachronism.


" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden

 

[ScottyUK]

If you connect a winding designed for 230V across the 400V line then the insulation won't be the immediate problem because the stator iron will magnetically saturate because there are insufficient turns in the winding for the higher voltage. If the supply fuses or breaker doesn't trip pretty much immediately then the insulation quickly will become an issue as the winding catches fire.

With a 400V supply you can only use star-delta starting with a motor rated at 400V/690V, but as jraef has already said star-delta is an outmoded technology which doesn't match the capability of a modern soft start.

 

[Parchie]

Any motor would be very happy when supplied with the correct voltage at its phases. That said, a 400V motor would be happy when supplied with 400V power.

As for the method of starting, please do away with star-delta scheme if you can.

 

[waross]

A 400 Volt, 60 Hertz motor may not be as happy with 400 Volts, 50 Hertz power.

Bill
--------------------
"Why not the best?"
Jimmy Carter